package com.bianmaba.spring.security.database.access;

import com.bianmaba.spring.security.database.access.intercept.DatabaseSecurityMetadataSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.core.annotation.Order;
import org.springframework.security.access.AccessDecisionManager;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.access.ConfigAttribute;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.stereotype.Service;

import java.util.Collection;
import java.util.Iterator;

import static com.bianmaba.spring.security.autoconfig.WebSecurityAutoConfiguration.ORDER;


@Service
@ConditionalOnClass({WebSecurityConfigurerAdapter.class})
//如果此类加载前已经存在实例，则此类将不会被实例化
@ConditionalOnMissingBean({DatabaseAccessDecisionManager.class})
@Order(ORDER)//配置初始化排序，此值越低，越靠前，但@Import引入的类此注解无效
public class DatabaseAccessDecisionManager implements AccessDecisionManager {
    protected static final Logger LOG = LoggerFactory.getLogger(DatabaseAccessDecisionManager.class);

    public DatabaseAccessDecisionManager() {
        if (this.getClass().getName().equals(DatabaseAccessDecisionManager.class.getName())) ;
        {
            LOG.info("加载访问决策管理器(order=" + ORDER + "):" + this.getClass().getName());
        }
    }

    public void decide(Authentication authentication, Object object, Collection<ConfigAttribute> configAttributes)
            throws AccessDeniedException {

        if (configAttributes == null) {
            return;
        }
        // 所请求的资源拥有的权限(一个资源对多个权限)
        Iterator<ConfigAttribute> iterator = configAttributes.iterator();

        ConfigAttribute configAttribute = null;
        String needPermission = null;
        boolean hashNext = iterator.hasNext();
        while (hashNext) {
            configAttribute = iterator.next();
            // 访问所请求资源所需要的权限
            needPermission = configAttribute.getAttribute();
            // 用户所拥有的权限authentication
            for (GrantedAuthority ga : authentication.getAuthorities()) {
                if (needPermission.equals(ga.getAuthority())) {
                    return;
                }
            }
            hashNext = iterator.hasNext();
        }
        // 没有权限让我们去捕捉
        throw new AccessDeniedException("Access is denied");
    }

    public boolean supports(ConfigAttribute attribute) {
        return true;
    }

    public boolean supports(Class<?> clazz) {
        return true;
    }

}
